Light panels that are used for decorative lighting have a light panel that from its face radiates a soft light. The entire face of the panel appears to glow.
In one example a light panel comprises a translucent or transparent pane and several point light sources such as light emitting diodes LEDs. The point light sources are distributed around the perimeter of the pane. They are fixed to the sides of the pane. The light sources radiate light into the pane through the perimeter surface of the pane. Light shines out from the pane through the front face of the pane and the back face of the pane. Etchings in the surface of the panel may be used to transmit the light further. The back face of the pane may be covered with a reflector such as a silvered or white back layer in order to reflect light through the front face of the pane.
An unwanted effect of illuminating a light panel with point light sources that are distributed around the perimeter of the panel is that uneven illumination occurs around the perimeter of the pane where there are sometimes alternating bright ‘hot spots’ and dark areas. Areas of the face nearest to the point sources glow most brightly. These alternating hotspots and dark areas spoil the even glow of the face of the panel. For example where a wall or ceiling of a room is to be illuminated with a cool glow by a light panel, a consistent, or uniform or non-mottled intensity of the glow across the entire face of the pane is desirable for its appearance.
In another example of a light panel, a translucent or transparent pane has point light sources such as light emitting diodes located in a slot in the face of the pane. The slot is aligned with the perimeter edge of the pane and the diodes shine inwards towards the center of the pane. As in the aforementioned example the light shines out of the pane through the front face of the pane and the back face of the pane and may be transmitted further by etchings. The slot gives rise to a bright strip adjacent the perimeter edge of the pane. The areas of the surface of the pane closest to the diodes in the slot glow most brightly. These disturbances and uneven light intensity from the face of the pane are undesirable.
In another example of a light panel LED lights are distributed evenly across an entire face of the pane and embedded into the pane or over the face of the pane or behind the pane. In this arrangement the entire face of the pane is mottled by bright areas close to the diodes and dark areas between the diodes.
The face of a light panel may be used as a backlight for a thin polymer, canvas or glass sheet or other material/product which is translucent or transparent having pleasant colours and images printed thereon or attached thereto. The sheet is known in the art as a slide or surface design layer. A light panel with a mottled face and uneven areas of brightness can spoil the view of colours and images on the slide resulting in poor visual impact.